In late March 2020, the Centers for Medicare & Medicaid Services (CMS) released projections of US national health spending that predicted growth from the 2019 level of 17.8% of gross domestic product (GDP) to 19.7% over the next 10 years.1 Through no fault of their own, the CMS prognosticators are poised to take their place in history beside economist Irving Fischer, who announced that “stock prices have reached what looks like a permanently high plateau” shortly before the market crash of 1929 that marked the start of the Great Depression. The coronavirus disease 2019 (COVID-19) pandemic is likely to result in year-over-year changes in both health care spending and GDP that are without precedent. Because the ratio of these 2 numbers, the share of health care in the GDP, receives so much attention in public policy, it is worth thinking about how large these changes may be, and more importantly, what they mean.